A blunt cardiac injury is an injury to the heart as the result of blunt trauma, typically to the anterior chest wall. It can result in a variety of specific injuries to the heart, the most common of which is a myocardial contusion, which is a term for a bruise (contusion) to the heart after an injury. Other injuries which can result include septal defects and valvular failures. The right ventricle is thought to be most commonly affected due to its anatomic location as the most anterior surface of the heart. Myocardial contusion is not a specific diagnosis and the extent of the injury can vary greatly. Usually, there are other chest injuries seen with a myocardial contusion such as rib fractures, pneumothorax, and heart valve injury. When a myocardial contusion is suspected, consideration must be given to any other chest injuries, which will likely be determined by clinical signs, tests, and imaging.

The signs and symptoms of a myocardial contusion can manifest in different ways in people which may also be masked by the other injuries. It is recommended that people with blunt chest trauma receive an electrocardiogram to determine if there are any irregularities with cardiac function. The presentation of an abnormal heart rhythm after sustaining a myocardial contusion can be delayed for up to 72 hours.

Onset may be rapid or more gradual. Symptoms typically include those of cardiogenic shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause.

Cardiac tamponade, also known as pericardial tamponade, is when fluid in the pericardium (the sac around the heart) builds up and results in compression of the heart. Onset may be rapid or more gradual. Symptoms typically include those of cardiogenic shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause.

Common causes include cancer, kidney failure, chest trauma, and pericarditis. Other causes include connective tissue diseases, hypothyroidism, aortic rupture, and following cardiac surgery. In Africa, tuberculosis is a relatively common cause.

Diagnosis may be suspected based on low blood pressure, jugular venous distension, pericardial rub, or quiet heart sounds. The diagnosis may be further supported by specific electrocardiogram (ECG) changes, chest X-ray, or an ultrasound of the heart. If fluid increases slowly the pericardial sac can expand to contain more than 2 liters; however, if the increase is rapid as little as 200 mL can result in tamponade.

When tamponade results in symptoms, drainage is necessary. This can be done by pericardiocentesis, surgery to create a pericardial window, or a pericardiectomy. Drainage may also be necessary to rule out infection or cancer. Other treatments may include the use of dobutamine or in those with low blood volume, intravenous fluids. Those with few symptoms and no worrisome features can often be closely followed. The frequency of tamponade is unclear. One estimate from the United States places it at 2 per 10,000 per year.

Traumatic cardiac arrest (TCA) is a condition in which the heart has ceased to beat due to blunt or penetrating trauma, such as a stab wound to the thoracic area. It is a medical emergency which will always result in death without prompt advanced medical care. Even with prompt medical intervention, survival without neurological complications is rare. There are no definitive protocols in place in how to manage traumatic cardiac arrest, but certain people benefit from the use of a thoracotomy in order to gain access and repair damage from the injury. Traumatic cardiac arrest is a complex form of cardiac arrest often derailing from Advanced Cardiac Life Support in the sense that the emergency team must first establish the cause of the traumatic arrest and reverse these effects, for example hypovolemia and haemorrhagic shock due to a penetrating injury.

Hemothorax tends to occur following blunt or penetrating trauma to the thorax or thoracoabdominal area. It may also follow thoracic surgery, or may be spontaneous. Chest pain, dyspnea, and tachypnea are common presenting features. Other symptoms of hemothorax are dependent on the mechanism of injury, but may include:

- Cyanosis

- Decreased or absent breath sounds on affected side

- Tracheal deviation to unaffected side

- Dull resonance on percussion

- Unequal chest rise

- Tachycardia

- Hypotension

- Pale, cool, clammy skin

- Possible subcutaneous emphysema

- Narrowing pulse pressure

The effects of a circulatory collapse vary based on the type of collapse it is. Peripheral collapses usually involve abnormally low blood pressure and result in collapsed arteries and/or veins, leading to oxygen deprivation to tissues, organs, and limbs.

Acute collapse can result from heart failure causing the primary vessels of the heart to collapse, perhaps combined with cardiac arrest.

The condition is difficult to detect and may go unnoticed, because many patients have no specific symptoms. Diagnosis is further complicated by the fact that many patients with the injury experienced multiple other serious injuries as well, so the attention of hospital staff may be distracted from the possibility of aortic rupture. In fact most cases occur along with other injuries.

A common symptom is unusually high blood pressure in the upper body and very low blood pressure in lower limbs. Another symptom is renal failure where the creatinine level shoots very high and urine output becomes negligible. In most cases, however, the doctors would misinterpret renal failure as due to issues with the kidney itself and may recommend dialysis.

Though not completely reliable, chest X-rays are the first-line treatment, initially used to diagnose this condition when the patient is unstable and cannot be sent to the CT bay. The preferred method of diagnosis used to be CT angiogram until it was found to cause complications in some people; now it is reserved for when CT scans are inconclusive.

The classical findings on a chest X-ray will be widened mediastinum, apical cap, and displacement of the trachea, left main bronchus, or nasogastric tube. A normal chest x-ray does not exclude transection, but will diagnose conditions such as pneumothorax or hydrothorax. The aorta may also be torn at the point where it is connected to the heart. The aorta may be completely torn away from the heart, but patients with such injuries rarely survive very long after the injury; thus it is much more common for hospital staff to treat patients with partially torn aortas. When the aorta is partially torn, it may form a "pseudoaneurysm". In patients who do live long enough to be seen in a hospital, a majority have only a partially torn blood vessel, with the outermost adventitial layer still intact. In some of these patients, the adventitia and nearby structures within the chest may serve to prevent severe bleeding. After trauma, the aorta can be assessed by a CT angiogram or a direct angiogram, in which contrast is introduced into the aorta via a catheter.

Traumatic aortic rupture, also called traumatic aortic disruption or transection, is a condition in which the aorta, the largest artery in the body, is torn or ruptured as a result of trauma to the body. The condition is frequently fatal due to the profuse bleeding that results from the rupture. Since the aorta branches directly from the heart to supply blood to the rest of the body, the pressure within it is very great, and blood may be pumped out of a tear in the blood vessel very rapidly. This can quickly result in shock and death. Thus traumatic aortic rupture is a common killer in automotive accidents and other traumas, with up to 18% of deaths that occur in automobile collisions being related to the injury. In fact, aortic disruption due to blunt chest trauma is the second leading cause of injury death behind traumatic brain injury.

Aortic rupture can also be caused by non-traumatic mechanisms, particularly abdominal aortic aneurysm rupture.

A very large range of medical conditions can cause circulatory collapse. These include, but are not limited to:

- Surgery, particularly on patients who have lost blood.

- Blood clots, including the use of some platelet-activating factor drugs in some animals and humans

- Dengue Fever

- Severe dehydration

- Shock (including, among other types, many cases of cardiogenic shock- e.g., after a myocardial infarction or during heart failure; distributive shock, hypovolemic shock, resulting from large blood loss; and severe cases of septic shock)

- Heart Disease (myocardial infarction- heart attack; acute or chronic congestive or other heart failure, ruptured or dissecting aneurysms; large, especially hemorrhagic, stroke; some untreated congenital heart defects; failed heart transplant)

- Superior mesenteric artery syndrome

- Drugs that affect blood pressure

- Drinking seawater

- As a complication of dialysis

- Intoxicative inhalants

Presentation may be subtle; people with mild contusion may have no symptoms at all. However, pulmonary contusion is frequently associated with signs (objective indications) and symptoms (subjective states), including those indicative of the lung injury itself and of accompanying injuries. Because gas exchange is impaired, signs of low blood oxygen saturation, such as low concentrations of oxygen in arterial blood gas and cyanosis (bluish color of the skin and mucous membranes) are commonly associated. Dyspnea (painful breathing or difficulty breathing) is commonly seen, and tolerance for exercise may be lowered. Rapid breathing and a rapid heart rate are other signs. With more severe contusions, breath sounds heard through a stethoscope may be decreased, or rales (an abnormal crackling sound in the chest accompanying breathing) may be present. People with severe contusions may have bronchorrhea (the production of watery sputum). Wheezing and coughing are other signs. Coughing up blood or bloody sputum is present in up to half of cases. Cardiac output (the volume of blood pumped by the heart) may be reduced, and hypotension (low blood pressure) is frequently present. The area of the chest wall near the contusion may be tender or painful due to associated chest wall injury.

Signs and symptoms take time to develop, and as many as half of cases are asymptomatic at the initial presentation. The more severe the injury, the more quickly symptoms become apparent. In severe cases, symptoms may occur as quickly as three or four hours after the trauma. Hypoxemia (low oxygen concentration in the arterial blood) typically becomes progressively worse over 24–48 hours after injury. In general, pulmonary contusion tends to worsen slowly over a few days, but it may also cause rapid deterioration or death if untreated.

A pulmonary laceration is a chest injury in which lung tissue is torn or cut. An injury that is potentially more serious than pulmonary contusion, pulmonary laceration involves disruption of the architecture of the lung, while pulmonary contusion does not. Pulmonary laceration is commonly caused by penetrating trauma but may also result from forces involved in blunt trauma such as shear stress. A cavity filled with blood, air, or both can form. The injury is diagnosed when collections of air or fluid are found on a CT scan of the chest. Surgery may be required to stitch the laceration, to drain blood, or even to remove injured parts of the lung. The injury commonly heals quickly with few problems if it is given proper treatment; however it may be associated with scarring of the lung or other complications.

A hemothorax is a type of pleural effusion in which blood accumulates in the pleural cavity. This excess fluid can interfere with normal breathing by limiting the expansion of the lungs. The term is from "" + "thorax".

Pulmonary contusion and laceration are injuries to the lung tissue. Pulmonary laceration, in which lung tissue is torn or cut, differs from pulmonary contusion in that the former involves disruption of the macroscopic architecture of the lung, while the latter does not. When lacerations fill with blood, the result is pulmonary hematoma, a collection of blood within the lung tissue. Contusion involves hemorrhage in the alveoli (tiny air-filled sacs responsible for absorbing oxygen), but a hematoma is a discrete clot of blood not interspersed with lung tissue. A collapsed lung can result when the pleural cavity (the space outside the lung) accumulates blood (hemothorax) or air (pneumothorax) or both (hemopneumothorax). These conditions do not inherently involve damage to the lung tissue itself, but they may be associated with it. Injuries to the chest wall are also distinct from but may be associated with lung injuries. Chest wall injuries include rib fractures and flail chest, in which multiple ribs are broken so that a segment of the ribcage is detached from the rest of the chest wall and moves independently.

Signs and symptoms vary depending on what part of the tracheobronchial tree is injured and how severely it is damaged. There are no direct signs of TBI, but certain signs suggest the injury and raise a clinician's suspicion that it has occurred. Many of the signs and symptoms are also present in injuries with similar injury mechanisms such as pneumothorax. Dyspnea and respiratory distress are found in 76–100% of people with TBI, and coughing up blood has been found in up to 25%. However, isolated TBI does not usually cause profuse bleeding; if such bleeding is observed it is likely to be due to another injury such as a ruptured large blood vessel. The patient may exhibit dysphonia or have diminished breath sounds, and rapid breathing is common. Coughing may be present, and stridor, an abnormal, high-pitched breath sound indicating obstruction of the upper airway can also occur.

Damage to the airways can cause subcutaneous emphysema (air trapped in the subcutaneous tissue of the skin) in the abdomen, chest, neck, and head. Subcutaneous emphysema, present in up to 85% of people with TBI, is particularly indicative of the injury when it is only in the neck. Air is trapped in the chest cavity outside the lungs (pneumothorax) in about 70% of TBI. Especially strong evidence that TBI has occurred is failure of a pneumothorax to resolve even when a chest tube is placed to rid the chest cavity of the air; it shows that air is continually leaking into the chest cavity from the site of the tear. Air can also be trapped in the mediastinum, the center of the chest cavity (pneumomediastinum). If air escapes from a penetrating injury to the neck, a definite diagnosis of TBI can be made. Hamman's sign, a sound of crackling that occurs in time with the heartbeat, may also accompany TBI.

The most common symptom of pulmonary edema is difficulty breathing, but may include other symptoms such as coughing up blood (classically seen as pink, frothy sputum), excessive sweating, anxiety, and pale skin. Shortness of breath can manifest as orthopnea (inability to lie down flat due to breathlessness) and/or paroxysmal nocturnal dyspnea (episodes of severe sudden breathlessness at night). These are common presenting symptoms of chronic pulmonary edema due to left ventricular failure. The development of pulmonary edema may be associated with symptoms and signs of "fluid overload"; this is a non-specific term to describe the manifestations of left ventricular failure on the rest of the body and includes peripheral edema (swelling of the legs, in general, of the "pitting" variety, wherein the skin is slow to return to normal when pressed upon), raised jugular venous pressure and hepatomegaly, where the liver is enlarged and may be tender or even pulsatile. Other signs include end-inspiratory crackles (sounds heard at the end of a deep breath) on auscultation and the presence of a third heart sound.

Complications are not common but include infection, pulmonary abscess, and bronchopleural fistula (a fistula between the pleural space and the bronchial tree). A bronchopleural fistula results when there is a communication between the laceration, a bronchiole, and the pleura; it can cause air to leak into the pleural space despite the placement of a chest tube. The laceration can also enlarge, as may occur when the injury creates a valve that allows air to enter the laceration, progressively expanding it. One complication, air embolism, in which air enters the bloodstream, is potentially fatal, especially when it occurs on the left side of the heart. Air can enter the circulatory system through a damaged vein in the injured chest and can travel to any organ; it is especially deadly in the heart or brain. Positive pressure ventilation can cause pulmonary embolism by forcing air out of injured lungs and into blood vessels.

Commotio cordis (Latin, "agitation of the heart") is an often lethal disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region), at a critical time during the cycle of a heart beat causing cardiac arrest. It is a form of ventricular fibrillation (V-Fib), not mechanical damage to the heart muscle or surrounding organs, and not the result of heart disease. The fatality rate is about 65% even with prompt CPR and defibrillation, and more than 80% without.

Commotio cordis occurs mostly in boys and young men (average age 15), usually during sports, most frequently baseball, often despite a chest protector. It is usually caused by a projectile, but can also be caused by the blow of an elbow or other body part. Being less developed, the thorax of an adolescent is likely more prone to this injury given the circumstances.

The phenomenon was confirmed experimentally in the 1930s, with research in anaesthetized rabbits, cats and dogs.

Breath sounds on the side of the rupture may be diminished, respiratory distress may be present, and the chest or abdomen may be painful. Orthopnea, dyspnea which occurs when lying flat, may also occur, and coughing is another sign. In people with herniation of abdominal organs, signs of intestinal blockage or sepsis in the abdomen may be present. Bowel sounds may be heard in the chest, and shoulder or epigastric pain may be present. When the injury is not noticed right away, the main symptoms are those that indicate bowel obstruction.

Pulmonary edema is fluid accumulation in the tissue and air spaces of the lungs. It leads to impaired gas exchange and may cause respiratory failure. It is due to either failure of the left ventricle of the heart to remove blood adequately from the pulmonary circulation (cardiogenic pulmonary edema), or an injury to the lung parenchyma or vasculature of the lung (noncardiogenic pulmonary edema). Treatment is focused on three aspects: firstly improving respiratory function, secondly, treating the underlying cause, and thirdly avoiding further damage to the lung. Pulmonary edema, especially acute, can lead to fatal respiratory distress or cardiac arrest due to hypoxia. It is a cardinal feature of congestive heart failure. The term is from the Greek (oídēma, "swelling"), from οἰδέω (oidéō, "I swell").

Lesions can be transverse, occurring between the rings of the trachea, longitudinal or spiral. They may occur along the membranous part of the trachea, the main bronchi, or both. In 8% of ruptures, lesions are complex, occurring in more than one location, with more than one type of lesion, or on both of the main bronchi and the trachea. Transverse tears are more common than longitudinal or complex ones. The laceration may completely transect the airway or it may go only partway around. Partial tears that do not go all the way around the circumference of the airway do not allow a lacerated airway to become completely detached; tears that encircle the whole airway can allow separation to occur. Lacerations may also be classified as complete or incomplete. In an incomplete lesion, a layer of tissue surrounding the bronchus remains intact and can keep the air in the airway, preventing it from leaking into the areas surrounding the airways. Incomplete lacerations may require closer scrutiny to detect and may not be diagnosed right away.

Bronchial injuries are divided into those that are accompanied by a disruption of the pleura and those that are not; in the former, air can leak from the hole in the airway and a pneumothorax can form. The latter type is associated with more minor signs; pneumothorax is small if it occurs at all, and although function is lost in the part of the lung supplied by the injured bronchus, unaffected parts of the lungs may be able to compensate.

Most TBI that results from blunt trauma occurs within the chest. The most common tracheal injury is a tear near the carina or in the membranous wall of the trachea. In blunt chest trauma, TBI occurs within 2.5 cm of the carina 40–80% of the time. The injury is more common in the right main bronchus than the left, possibly because the former is near vertebrae, which may injure it. Also, the aorta and other tissues in the mid chest that surround the left main bronchus may protect it. Another possibility is that people with left main bronchus injuries are more likely to also have other deadly injuries and therefore die before reaching hospital, making them less likely to be included in studies that determine rates of injuries.

The primary concern in any splenic trauma is internal hemorrhage, though the exact amount of hemorrhage may be small or large, depending on the nature and degree of injury. Small or minor injuries often heal spontaneously, especially in children. Larger injuries hemorrhage extensively, often causing hemorrhagic shock. A splenic hematoma sometimes ruptures, usually in the first few days, although rupture can occur from hours to even months after injury.

The primary symptom, hemorrhage, presents differently depending on the degree of injury, with the symptoms of major hemorrhage, shock, abdominal pain, and distention being clinically obvious. Minor hemorrhage often presents as upper left quadrant pain. Patients with unexplained left upper quadrant pain, particularly if there is evidence of hypovolemia or shock, are generally inquired regarding any recent trauma.

In minor injuries with little bleeding, there may be abdominal pain, tenderness in the epigastrium and pain in the left flank. Often there is a sharp pain in the left shoulder, known as Kehr's sign. In larger injuries with more extensive bleeding, signs of hypovolemic shock are most prominent. This might include a rapid pulse, low blood pressure, rapid breathing, paleness, and anxiety.

The signs and symptoms of carotid artery dissection may be divided into ischemic and non-ischemic categories:

"Non-ischemic signs and symptoms"

- Localised headache, particularly around one of the eyes.

- Neck pain

- Decreased pupil size with drooping of the upper eyelid (Horner syndrome)

- Pulsatile tinnitus

"Ischemic signs and symptoms"

- Temporary vision loss

- Ischemic stroke

The main symptom is usually severe central chest pain. Other symptoms include laboured breathing, voice distortion (as with helium) and subcutaneous emphysema, specifically affecting the face, neck, and chest. Pneumomediastinum can also be characterized by the shortness of breath that is typical of a respiratory system problem. It is often recognized on auscultation by a "crunching" sound timed with the cardiac cycle (Hamman's crunch).

Pnemomediastinum may also present with symptoms mimicking cardiac tamponade as a result of the increased intrapulmonary pressure on venous flow to the heart.